1. Field of the Invention
The invention relates to a steering system.
2. Description of Related Art
A steering column described in US Patent Application Publication No. 2009/0013817 (US 2009/0013817 A1) includes a setting unit, a holding unit, a tooth plate, a press-on member, and a clamp bolt. The setting unit can be pivoted to adjust the position of the steering column in a certain adjustment direction. The holding unit holds the setting unit. To the setting unit, a jacket unit that holds a steering shaft is attached. The holding unit has a plurality of teeth arranged in the adjustment direction. The tooth plate also has a plurality of teeth arranged in the adjustment direction. The clamp bolt is inserted through the press-on member and the tooth plate, and can be pivoted together with the setting unit.
By operating a lever attached to the clamp bolt, the press-on member can be moved toward the holding unit. When the press-on member moves toward the holding unit, the tooth plate is pressed against the press-on member to move toward the holding unit. When the teeth of the moving tooth plate enter spaces between the teeth of the holding unit, the teeth of the holding unit and the teeth of the tooth plate mesh with each other. Thus, the position of the jacket unit in the adjustment direction is fixed.
By contrast, when the teeth of the tooth plate ride on the teeth of the holding unit without entering the spaces between the teeth of the holding unit, the press-on member bends the tooth plate to press the holding unit. From this state, when the tooth plate moves in the adjustment direction, the tooth plate returns to the previous state in which the tooth plate is not bent, and the teeth of the tooth plate enter the spaces between the teeth of the holding unit. This causes the teeth of the holding unit and the teeth of the tooth plate to mesh with each other, thereby fixing the position of the jacket unit in the adjustment direction.
The adjustment direction defined in US 2009/0013817 A1 is an intersecting direction vertically intersecting the axial direction of the steering shaft. In the steering column of US 2009/0013817 A1, when a vehicle is subjected to strong impact in a collision, for example, with the teeth of the tooth plate riding on the teeth of the holding unit without meshing with the teeth of the holding unit, the jacket unit pivots in the intersecting direction so as to cause the teeth of the holding unit and the teeth of the tooth plate to mesh with each other. In this case, the jacket unit pivots by a length that is substantially equal to the pitch of the teeth at the maximum. In the event of a vehicle collision, in order to stabilize the position of a steering member coupled to the steering shaft, it is desired to reduce the pivoting amount of the jacket unit as small as possible.